OH...MY...GOD....That is an amazing link...
I've known some of the uses of は and が, but I didn't know they could be used at the same time (except with inner clauses).
However...I am still a little confused about why 「みかのことはわすれません」 would use は. I understand now that は can replace を but, why it does so in this instance I'm a bit lost on.
The example used in that link is:
「えはがかがかいた」
They state this could be in response to the question, "Who drew the picture?"
えis the topic, or old information.
がか is new information.
So in this case, は is being used to emphasize that it's the picture that's being talked about (even though it could have been easily left out of the sentence entirely).
So I understand that usage (though keeping topic and focus straight in my head is taking a little work lol).
With 「みかのことはわすれません」, I can see why the を can be replaced with は but I'm not sure why you would in this instance. Obviously I don't have context to tell me what has or hasn't been talked about, but at the same time.......Actually, I'm going to derail that thought and just ask a question.
Can something be marked with は even if it hasn't been explicitly stated previously? In this instance, since the people seem to be saying goodbye, can 「みかのこと」 be marked with は simply because みか is presumably one of the participants in the conversation?
By the way...sorry
@Yuta73 ...I've sort of hijacked your thread..